Tabulating mechanism for a dual pitch escapement

ABSTRACT

A type carriage of a single element typewriter is movable in a letter feed direction under the control of an escapement mechanism having interchangeable escapement racks of different pitches for use with interchangeable print elements having type characters requiring different character spacing. A tabulating mechanism having a character spacing corresponding to only one of the interchangeable escapement racks is useable with the alternate escapement rack by supporting a tab member for movement relative to the movable carriage and providing a tab control member for imparting an oscillatory movement to the tab member during a tabulating operation so that the tab member will engage set tab stops at positions corresponding to the pitch of the alternate escapement rack.

United States Patent [191 Gottsmann [75] Inventor:HelmutGottsmann,Nuernberg,

. Germany [73] Assignee: Triumph Werks Nuernberg A.G.,

Nuernberg, Germany [22] Filed: May 10, 1973 [21] Appl. No.: 359,129

[30] Foreign Application Priority Data May 16, 1972 Germany 2223689 [52]U.S. Cl. 197/176, 197/82, 197/84 R [51] Int. Cl B4lj 25/18 [58] Field ofSearch 197/70, 82, 84 R, 84 A,

[56] References Cited UNITED STATES PATENTS 1,964,748 7/1934 Trego197/176 3,225,886 12/1965 Cetran et al. 19 7/84 R 3,346,087 10/1967Colombo et al. 197/187 X 3,540,565 11/1970 Hanftet al 197/176 3,547,24512/1970 Okcuoglu et al 197/84 R X OTHER PUBLICATIONS IBM TechnicalDisclosure Bulletin, Dual-Pitch Tab 1 Jan.7,1975

Rack," H. R. Kruspe, Vol. 8 No. 5. October 1965, page 793.

Primary E xaminer-Ernest T. Wright, Jr. Attorney, Agent, or Firm-JosephR. Spalla [57] ABSTRACT A type carriage of a single element typewriteris movable in a letter feed direction under the control of an escapementmechanism having interchangeable escapement racks of different pitchesfor use with interchangeable print elements having type charactersrequiring different character spacing. A tabulating mechanism having acharacter spacing corresponding to only one of the interchangeableescapement racks is useable with the alternate escapement rack bysupporting a tab member for movement relative to the movable. carriageand providing a tab control member for imparting an oscillatory movementto the tab member during a tabulating operation so that the tab memberwill engage set tab stops at positions corresponding to the pitch of thealternate escapement rack.

4 Claims, 4 Drawing Figures PATENTEDJAN W5v 3,858,706

SHEEI 10F 2 Fig.2

PATENTEU JAN 7 75 SHEET 2 0F 2 TABULATING MECHANISM FOR A DUAL PITCHESCAPEMENT This invention relates to a tabulating mechanism for atypewriter or similar business machine, and more particularly to atabulating mechanism for a single element typewriter capable ofutilizing interchangeable print elements having type characters ofdifferent character spacing.

In a typewriter or similar business machine, a carriage is slidablymounted on a typewriter frame for enabling relative movement between theprinting apparatus and a recording medium supported on a suitableplaten, and a line of type is printed by moving the carriage in a letterfeed direction in incremental steps each corresponding to the size ofthe type characters being printed. As is conventional, the steppingmovement is effected by an escapement mechanism which includes a rackhaving a series of teeth with a pitch corresponding to the size of thetype characters being printed. In addition, the typewriter is providedwith a tabulating mechanism for disengaging the escapement mechanism andeffecting a free sliding movement of the carriage in the letter feeddirection to a predetermined position whereupon the movement of thecarriage is arrested and returned to the control of the escapementmechanism. Typically, the tabulating mechanism includes a tab rackhaving a plurality of tabs which may be set to stop the carriage duringa tabulating operation and each of the tabs represent a position alongthe line of type corresponding to a tooth of the escapement rack.

As is known, printing with a single element typewriter may be effectedutilizing interchangeable print elements having different type styles,numbers, symbols or combinations thereof. Moreover, the interchangeableprint elements may have type characters of different sizes, for exampleelite and pica which require character spacing along a line of type of2.12 mm. and 2.54 mm. respectively. However, a change of print elementsinvolving a change in character spacing also requires a modification ofthe escapement mechanism so as to bring into operation an escapementrack having teeth with a pitch corresponding to the character spacing ofthe print element. Such a modification of the escapement mechanism,however, creates a difference between the character spacing of theescapement mechanism and the character spacing of the tabulatingmechanism which may result in tabulating errors.

In the past, single element typewriters capable of utilizinginterchangeable type elements of different character spacings have beenprovided with alternate escapement racks and a tabulating mechanismcapable of operating with either escapement rack. Such an arrangement isshown, for example, in German published application DT-AS 1,815,871 andcorresponding US. Pat. No. 3,540,565 and includes a tabulating mechanismhaving settable tabs spaced apart at varying intervals. However, such anarrangement is costly, difficult to manufacture and subject totabulating errors due to the different space intervals between the tabs.Accordingly, an object of the present invention is to provide atabulating mechanism having tab stops evenly spaced along a tab rack andoperable in conjunction with an escapement mechanism capable ofeffecting escapement movements corresponding to type characters ofdifferent sizes.

Another object of the invention is to provide a tabulating mechanismhaving evenly spaced tab stops corresponding to a particular characterspacing and capable of compensating for a difference in pitch with acooperating escapement mechanism.

Still other objects, features and advantages of the present inventionwill become apparent to those skilled in the art from a reading of thefollowing detailed description of a single embodiment of the invention,taken in conjunction with the accompanying drawing, wherein:

FIG. 1 is a diagrammatic view of a tabulating mechanism constructed inaccordance with the present invention and illustrating in a restposition an escapement mechanism having a pitch corresponding to thetype character spacing of the'tabulating mechanism;

FIG. 2 is a view similar to FIG. 11 and illustrating the tabulatingmechanism undergoing a tabulating operation in conjunction with anescapement rack having a pitch unequal to the character spacing of thetabulating mechanism;

FIG. 3 is a view similar to FIG. 2 and illustrating the operation of atabulating mechanism upon engagement with a settable tab; and

FIG. 4 illustrates diagrammatically the manner in which the tabulatingmechanism compensates for the difference between the pitch or characterspacing of the tab rack and differently pitched teeth of an escapementrack.

Referring now in detail to the figures in the drawing, there is shown anescapement mechanism, generally indicated 11, and a tabulatingmechanism, generally indicated 13, for controlling the movement of acarriage, generally designated by reference character C, which ismounted on a frame, generally designated by reference character F of atypewriter or similar business machine for slidable movement relativethereto. In printing a line of type, the carriage C is moved in a letterfeed direction under the control of the escapement mechanism 11 whichpermits the carriage C to move only one character space at a time, whilepermitting free movement of the carriage C in the opposite directionduring a carriage C return operation. To move the carriage quickly inthe letter feed direction to one or more predetermined positions, thetabulating mechanism 13 is actuated to disengage the escapementmechanism 11 and enable the carriage C to slide freely relative to thetypewriter frame F until the predetermined position is reached,whereupon the tabulating mechanism 13 operates to arrest the movement ofthe carriage C and return it to the control of the escapement mechanism11. Although the present invenion will be described in connection with atypewriter having a carriage C for transporting a single print element,it is to be understood that the invention could also be utilized in atypewriter having a reciprocating carriage C for transporting a papersupporting platen. Furthermore, the carriage C and the typewriter frameF as well as other portions of the typewriter are shown only generallysince they form no part of the present invention and may be desirablyconventional.

As shown, the escapement mechanism 11 includes a feed pawl 15 which ispivotally supported about a stud 17 associated with the carriage C forengagement with an escapement rack 19 which may be suitably mounted onthe frame F of the typewriter. The feed pawl 15 has a tooth 21 forengaging one of a series of evenly spaced teeth 23 formed on theescapement rack 19, and the feed pawl 15 is urged into engagement withthe escapement rack 19 by a spring 25 stretched between a projection 27of the feed pawl and a suitable portion of the typewriter. carriage C.Each of the teeth 23 formed on the escapement rack 19 represents acharacter space along the line of type, and the distance a between theteeth 23 of the escapement rack 19, hereinafter referred to as the pitchof the escapement rack, corresponds to the size of the type characterson the print element being transported by the carriage C. During eachsuccessive printing operation, the escapement mechanism 11 permits thecarriage C'to advance in the letter feed direction only one tooth 23 ata time, and no further description of the escapement mechanism 11 isbelieved necessary since the operation of the escapement mechanism 11for controlling the movement of the type carriage C relative to theframe F of the typewriter is well-known in the typewriter art.

As also shown, the tabulating mechanism 13 includes a control member 29in the form of a lever which is movable about the stud 17 associatedwith the carriage C and carries on one end a tab member 31 forengagement with a plurality of tab stops 33 of a tab rack generallydesignated by reference character R suitably mounted on the typewriterframe f. The tab stops 33 are equally spaced apart with a spacing acorresponding to that of the escapement rack 19, and each of the tabstops 33 may be set, as shown by the tab stop 33, in a conventionalmanner for engagement by a blade 35 of the tab member 31 during thetabulating operation. The stud 17 is received in a central elongatedopening37 of the control member 29 with one end of the elongated opening37 normally pressed against the stud 17 by a spring 39 stretched betweenthe control member 29 and a suitable portion of the carriage C forurging the control member 29 in the letter feed direction. The controlmember 29 has a projecting finger 40 for engaging the feed pawl 15 todisengage the escapement mechanism 11, while a bent ear 41 is formed atthe other end for engaging a latching mechanism, generally indicated 43.As shown, the latching mechanism 43 includes an L-shaped lever 45pivotally supported by a stud 46 on the carriage C with one arm 47engaging the bent car 41 of the control member 29 while the other arm 49is urged toward a stop abutment 51 by a spring 53 stretched between thearm 49 and a suitable portion of the carriage C.

In a tabulating operation, the control member 29 is pivoted from a restposition, as shown in FIG. I, to an operating position, as shown in FIG.2, to remove the feed pawl 15 from engagement with the escapement rack19 and enable the carriage C to slide freely in a letter feed directiontoward a set tab stop 33'. The pivoting of the control member 29 placesthe blade 35 of the tab member 31 in a position for engaging the set tabstop 33, and the control member 29 is held in the pivoted position bythe latching mechanism 43 which receives the bent ear 41 in a notch 55formed in the latching lever 45. Upon engagement of the tab blade 35with the set tab stop 33', the control member 29 is driven against theurging of the spring 39 until the opposite end of the elongated slot 37is pressed against the stud shown in FIG. 3, while the latching lever 45is pivoted into engagement with the stop abutment 51 under the urging ofthe spring 53. Subsequently, the control member 29 is pulled in theletter feed direction by the urging of the spring 39 until the end ofthe elongated slot 37 is pressed against the stud 17 as shown in FIG. 1.

As previously discussed, the single print element of the typewriter maybe replaced with another print element having type characters requiringa different or larger character spacing, for example, pica type. Toenable the carriage C to be advanced in a letter feed direction in stepscorresponding to the spacing of the larger type characters, theescapement mechanism 11 may be modified by replacing the escapement rack19 having the pitch a with an escapement rack 19 having a pitch b asshown in FIG. 2. Although not shown, such a substitution may be easilyaccomplished by pivotally supporting the two escapement racks l9, 19 foralternate movement into operating engagement with the feed pawl 15.However, with the substitution of the escapement rack 19' having thelarger character spacing, the settable tab stops 33 no longer have acharacter spacing corresponding to that of the escapement mechanism 11.

In accordance with the present invention, the tabulating mechanism 13 isdesigned to compensate for the 17 to bring the carriage C to a stop. Atthe same time,

difference in pitch between the escapement rack 19 and the tab stops 33so as to enable accurate tabulating operations to be carried out whenescapement rack 19' is operably associated with the feed pawl 15. Asshown, the tab member 31 is pivotally supported by a stud 32 on thecontrol member 29 and has an arm 57 urged against the control member 29by a spring 59 stretched between the arm 57 and a suitable portion ofthe control member 29. In addition, the tab member 31 has another arm 61carrying a suitable roller 63 for engagement with a tab member controlmeans. As shown, the tab member control means is in the form of a bail65 having a cyclically repeated camming surface 67 and which may besuitably supported on pivoted arms (not shown) whose free ends aresecured to stub shafts 68 on the ends of the bail 65 to permit itspivotal movement under manual control, for example, to a loweredoperating position as shown in FIGS. 2 and 3 when the escapement rack19' having the pitch b is brought into operative association with thefeed pawl 15.

Accordingly, when a tabulating operation is effected using theescapement rack 19', the pivoting of the control member 29 brings theroller 63 carried by the tab member 31 into engagement with the cammingsurface 67 of the operatively positioned bail 65 so as to effect anoscillatory movement of the tab blade 35 as the carriage C movesrelative to the typewriter frame F. As more particularly shown in FIG.4, the camming surface 67 of the bail 65 is designed to pivot the tabmember 31 so as to bring the tab blade 35 into engagement with set tabstops 33 at character spacings corresponding to the larger pitch of thealternate escapement rack 19'. Upon completion of the tabulatingoperation, the movement of the carriage C will be returned to thecontrol of the escapement mechanism 11 as previously described, and thetab member 31 will be removed from engagement with the operativelypositioned bail 65.

What is claimed is:

1. In a business machine having relatively movable first and secondelements, the combination comprising:

an escapement rack associated with said first element for relativemovement therewith andhaving a plurality of teeth formed thereon eachdefining a character space,

a feed pawl pivotally supported about a point on said second element forrelative movement therewith and having a tooth for engaging the teeth ofsaid escapement rack,

said feed paw] being resiliently urged into engagement with saidescapementrack for controlling the relative movement between said firstand second elements in a letter feed direction,

a control member pivotally supported about the point on said secondelement for disengaging said feed pawl from said escapement rack duringa tabulating operation to permit free relative movement between saidfirst and second elements in the letter feed direction,

a tab rack associated with said first element for relative movementtherewith and having a plurality of settable tab stops eachcorresponding to a character space different from the character spacedefined by the teeth of said escapement rack,

a tab member having a tab blade for engaging a set tab stop on said tabrack during a tabulating operation,

said tab member being pivotally supported on said control member forenabling the tab blade to be moved relative to said control member onsaid second element, and

tab member control means associated with said first element and operablein response to relative movement between said first and second elementsduring a tabulating operation for pivoting said tab member to alter theposition of said second element relative to said first element uponengagement of the tab blade with a set tab stop to compensate for thedifference in character spacing between the teeth of said engagementrack and the 'settable tab stops.

2. In a business machine according to claim 1:

said tab member having an arm for engaging a cam ming surface,

said tab member control means including a camming surface for engagingthe arm of said tab member to pivot the tab blade in an oscillatorymovement during free relative movement between said first and secondelements in the letter feed direction, and

said camming surface defining an oscillatory movement of said tab bladeto compensate for the difference in character spacing betweeen theescapement rack and the tab rack.

3. In a business machine according to claim 2:

said control member being slidably disposed about the point on saidsecond element,

latch means operable in response to the pivotal movement of said controlmember to effect free relative movement between said first and secondelements for holding said control member in the pivoted position, and

said control member being slidable about the point on said secondelement in response to the engagement of the tab blade with a set tabstop for being released from said latch means for pivotal movement toenable said feed pawl to reengage said escapement rack.

4. In a business machine according to claim 1:

said control member being slidably disposed about the point on saidsecond element,

latch means operable in response to the pivotal capement rack.

1. In a business machine having relatively movable first and secondelements, the combination comprising: an escapement rack associated withsaid first element for relative movement therewith and having aplurality of teeth formed thereon each defining a character space, afeed pawl pivotally supported about a point on said second element forrelative movement therewith and having a tooth for engaging the teeth ofsaid escapement rack, said feed pawl being resiliently urged intoengagement with said escapement rack for controlling the relativemovement between sAid first and second elements in a letter feeddirection, a control member pivotally supported about the point on saidsecond element for disengaging said feed pawl from said escapement rackduring a tabulating operation to permit free relative movement betweensaid first and second elements in the letter feed direction, a tab rackassociated with said first element for relative movement therewith andhaving a plurality of settable tab stops each corresponding to acharacter space different from the character space defined by the teethof said escapement rack, a tab member having a tab blade for engaging aset tab stop on said tab rack during a tabulating operation, said tabmember being pivotally supported on said control member for enabling thetab blade to be moved relative to said control member on said secondelement, and tab member control means associated with said first elementand operable in response to relative movement between said first andsecond elements during a tabulating operation for pivoting said tabmember to alter the position of said second element relative to saidfirst element upon engagement of the tab blade with a set tab stop tocompensate for the difference in character spacing between the teeth ofsaid engagement rack and the settable tab stops.
 2. In a businessmachine according to claim 1: said tab member having an arm for engaginga camming surface, said tab member control means including a cammingsurface for engaging the arm of said tab member to pivot the tab bladein an oscillatory movement during free relative movement between saidfirst and second elements in the letter feed direction, and said cammingsurface defining an oscillatory movement of said tab blade to compensatefor the difference in character spacing betweeen the escapement rack andthe tab rack.
 3. In a business machine according to claim 2: saidcontrol member being slidably disposed about the point on said secondelement, latch means operable in response to the pivotal movement ofsaid control member to effect free relative movement between said firstand second elements for holding said control member in the pivotedposition, and said control member being slidable about the point on saidsecond element in response to the engagement of the tab blade with a settab stop for being released from said latch means for pivotal movementto enable said feed pawl to reengage said escapement rack.
 4. In abusiness machine according to claim 1: said control member beingslidably disposed about the point on said second element, latch meansoperable in response to the pivotal movement of said control member toeffect free relative movement between said first and second elements forholding said control member in the pivoted position, and said controlmember being slidable about the point on said second element in responseto the engagement of the tab blade with a set tab stop for beingreleased from said latch means for pivotal movement to enable said feedpawl to reengage said escapement rack.